Oven door window



Sept. 5, 1967 v. .LEVANS OVEN DOOR WINDOW Filed Jan. 7, 1966 INVENTOR. l//A/cfA/r J. TVA/V5 United States Patent O f 3,339,541 OVEN DOOR WINDOW Vincent J. Evans, Rocky River, Ohio, assiguor to The Columbus Stove Company, Columbus, Ohio, a corporation of Ohio Filed Jan. 7, 1966, Ser. No. 519,203 Claims. (Cl. 126-200) This invention relates generally to oven door window units and more particularly to window units having a pair of glass panels spaced apart and mounted in the oven door between the door panel and an inner liner.

Heretofore such window units have generally employed two glass panels which are spaced apart by a spacer and secured together by means of a surrounding channel which clamps the two glass panels together and carries the supports for attaching the lunit to the door. Two glass panels have been used because they decrease the heat transfer and prevent the outer panel from becoming excessively hot. This creates a space between the glass panels into which dirt, gases and grease vapors from the interior of the oven can leak unless the space is effectively sealed. For that reason, various means have been used including gaskets and sealing strips in combination with the spacer and clamping channel to seal this interior space against the entry of such foreign matter.

However, these efforts have created problems because the sealing material must be capable of withstanding elevated temperatures up to 550 F. for long periods of time and the mounting channel and seal arrangement must be able to compensate for the thermal expansion of the glass panels and the metal frame and the fact that the metal and glass have different rates of thermal expansion. This has resulted in window units which have become increasingly complex and expensive.

It is therefore a principal object -of this invention to provide a novel window unit for an oven door having a pair of glass or other transparent panels cemented to a spacer between them and supported entirely by the spacer.

It is another object of this invention to provide a window unit as set forth in the preceding object which eliminates the need for an exterior frame around the edges of the glass panels.

It is another object of this invention to provide a Win- Idow unit as set forth in the preceding objects which minimizes heat conduction from the oven interior to the outside glass panel.

It is another object of this invention to provide a window unit as set forth in the preceding objects which provides an effective seal to prevent dirt, gases and grease vapors from entering the space between the glass panels.

It is' a further object of this invention to provide a window unit as set forth in the preceding objects which gives a positive and solid mounting for the unit which is resistant to vibration and shock without any tendency to Warp or distort either portions of the window unit or lthe door itself.

Further objects and advantages relating to the low cost of manufacture, simplicity of construction and ease of assembly without sacrifice of durability will readily become apparent to those skilled in the art upon a complete understanding of the invention, the preferred embodiment of which is shown in the accompanying drawings and described in the following detailed description.

In the drawings:

FIGURE 1 is a perspective view showing the window unit of this invention mounted in place on an oven door liner;

FIGURE 2 is an enlarged fragmentary View taken on line 2-2 of FIGURE 1 showing further details of the means for securing the Window unit to the door;

FIGURE 3 is a fragmentary cross-sectional view taken 3,339,541 l Patented Sept. 5, 1967 ICC on line 3--3 of FIGURE 1 showing the window unit installed in the door;

FIGURE 4 is a fragmentary View showing the construction -of the joint in the spacer channel; and

FIGURE 5 is an enlarged fragmentary view of an alternative arrangement for securing the glass panels to the spacer channel.

Referring to the drawings in greater detail, FIGURE 1 shows a window unit according to -the present invention mounted in an oven door of the type usedyon household ovens. The door has an inner door liner 10 formed of sheet steel having an offset recess 11 therein within which is an opening 12. The liner is formed with an inturned lip 14 around the opening 12 to stiften the liner and to position the window unit. The door liner 10 fits within the door 16, also made of sheet steel and the door 16 has an opening 17 arranged to be substantially in register with the liner opening 12 and an inturned lip 18 surrounds the door opening 17, also to position the window unit. In accordance with the usual construction, the space between the liner and the door may be lled with a suitable insulation 21 such as a mineral wool, or glass liber mat and a stiffening reinforcement 22 may be welded to the liner 10 to prevent warping thereof from the heat within the oven.

The window 4unit is assembled as a separate unit and secured to the door structure in alignment with the openings 12 and 17. The window unit has an inner glass panel 24 adjacent the liner 10 which is made of a generally thick heat resistant glass. The outer glass panel 26, not being exposed to high temperature, may ybe of ordinary window glass. The panels 24 and 26 are spaced apart by a spacer frame 28. This spacer frame is in the form of a -channel bent to be generally rectangular in shape having a web portion 30 and a pair of outwardly extending lips 31 and 32 adjacent to the glass panels 24 and 26, respectively. The exact shape of the spacer frame is determined by that of the door and liner openings 17 and 12, since the inner surface of the frame should be aligned with the lips 14 and 18 around the openings. The spacer frame may be made of any suitable material such as steel and if desired, may be polished or plated for decorative purposes since its interior surfaces are visible through the glass panels. The channel may be formed by bending from a continuous strip and the ends are joined together to allow the interior space between the panels to be sealed. For this purpose, one end of the channel has an offset tab 34 having a -Width equal to the space between the lips 31 and 32 and offset lby the 'thickness of the web portion 30. This offset tab 34 (see FIGURE 4) ts over the opposite end of the channel and is secured thereto by suitable means such as spot welding shown at 35.

The glass panels 24 and 26 are equal to or slightly larger than the spacer frame in size, so that they extend even with the outer edges of lips 31 and 32 are slightly beyond them. The panels are cemented to the sides of the spacer frame 28 by means of the adhesive or cement layer shown at 37 and 38. Because of the temperature to which the unit is exposed, the maximum being 550 F. in most household ovens, it is necessary that the adhesive chosen to secure the glass panels to the spacer channel must be chemically and physically stable up to the temperatures at least this high. Furthermore, the cement or adhesive must provide a strong bond to resist shock and vibration and must have stability so as not to lose any of its properties over a period of many years. Another important problem of the adhesive or cement is that it must remain fairly flexible so as to be `able to accommodate the different rates of thermal expansion of the glass panels and the metal spacer channel. Likewise, the adhesive must be resistant to any oils or stove cleaning materials to which it might be exposed.

The preferred adhesive is silicone rubber adhesive because of its stability, flexibility and compatibility with both glass and metal, but other adhesives such as exible epoxy adhesives can also be used. The assembly of the unit is quite simple, since it is only necessary to spread the adhesive over the spacer frame lips 31 and 32 and then press the glass panels lightly against the adhesive coated lips and allow the adhesive to cure. Because the adhesive extends all the way around the lips 31 and 32, it also provides an effective seal for the space between the panels to prevent the entrance of any gases, grease vapors or dirt which would discolor the panels and decrease visibility through them.

Because the glass panels 24 and 26 are rmly secured by the adhesive to the spacer frame 28, the unit may be mounted merely by supporting the spacer frame 28 without providing any additional support for the glass panels. For this purpose, the spacer frame 28 is provided with a plurality of projecting ears 40 secured t-o the channel member by welding as at 41. As shown, three ears are used but other numbers and arrangements may be used as desired. T-he door liner is provided with a projecting mounting bracket 43 adjacent each of the ears 40 and the mounting bracket is xedly secured to the door liner 10 by welding as at 44. Thus, the ears 40 tit in abutting Contact with the -brackets 43 to which they may be secured by suitable means such as screws 46.

Thus, it will be seen that when the door is assembled together, first the window unit is attached to the liner 10 by means of the ears 40 and mounting bracket 43, after which the insulation is put in place and the door member 16 secured thereto. In this position, the lip 14 on the door liner is in firm abutting contact with the inner glass panel 24, and likewise the lip 18 around the door opening 17 is in abutting contact with the outer glass panel 26. The result is an assembly that effectively seals the interior of the oven to prevent the escape of heat and vapors while allowing clear vision into the oven interior.

As previously indicated, the adhesive layers 37 and 38 must allow for differential expansion between the glass panels and the spacer channel. For this reason, it is desirable that these layers have a substantial thickness and that an adequate amount of cement or adhesive be used to allow the adhesive to flex with relative movement between the glass and metal without having it pulled loose from its bond to the spacer frame and the glass panels. For ease of applying the adhesive and to insure the presence of an adequate amount, it may be desirable to provide a groove 49 (see FIGURE 5) in the lips intermediate the inner and outer edges. This groove 49 will then extend the full length of the channel lip and will serve both as a guide for applying the adhesive and a reservoir in effect to insure that there is sufficient adhesive to allow the small relative shifting of the glass and metal under thermal expansion.

The adhesive layers 37 and 38 also act as insulating barriers to prevent heat transfer and conduction from the interior of the oven to the outer glass panel and the outer surface of the door. Because the inner glass panel 24 is exposed to the heat within the oven, it naturally becomes fairly hot. However, the adhesive layer 37, because the adhesive is an excellent insulator, greatly reduces the conduction of this heat to the spacer frame 28. Likewise, the other adhesive layer 38 greatly reduces heat conduction from the spacer frame to the outer panel 26. In addition, since the inturned lips 14 and 18 on the liner 10 and the door 16 contact only the glass panels, and since there is no exterior metal channel or clamping member extending between the liner and the door, conduction of heat to the door surface is minimized and both the metal door and outer glass panel 26 will have a minimum increase in temperature.

Although the invention has been shown and described in detail, it is recognized that various modifications and rearrangements will occur to those skilled in the art upon a full comprehension of the invention and may be resorted to without departing from the scope of the invention as defined in the claims.

What is claimed is:

1. A window unit for an oven door comprising a pair of spaced transparent panels, a spacer frame between said panels, said spacer frame extending continuously about an air space between said panels and with said panels substantially sealing said air space, said spacer frame having a pair of peripheral lips extending continuously about said spacer frame, one adjacent each of said panels, an adhesive layer between each of said lips and the adjacent panel securing and sealing said panel to said spacer frame, and mounting means on said spacer frame for mounting said window unit on an oven door, said adhesive layers and said mounting means constituting the sole means supporting said panels on said oven door.

2. A window unit as set forth in claim 1 wherein said adhesive layer is a silicone rubber stable at temperatures up to 550 F. and sufficiently liexible to accommodate differential thermal expansion and contraction of said panels and said spacer frame.

3. A window unit as set forth in claim 1 wherein each of said channel lip has a groove extending parallel to its edges intermediate the inner and outer edges of the associated adhesive layer.

4. A window unit as set forth in claim 1 wherein said adhesive layers prevent thermal conduction contact between said spacer frame and said panels and an insulating air gap extends continuously around the periphery of each of said panels to minimize heat transfer between the panels.

5. A window unit for an oven door comprising a pair of spaced glass panels, a metal spacer frame between said panels, said spacer frame extending continuously about an air space between said panels and with said panels substantially sealing said air space, said spacer frame being in the form of a channel member having a web section extending substantially perpendicular to said panels and having lip portions extending outward from said web section substantially parallel to said panels and adjacent thereto, said panels extending at all points at least as far as the outer edge of said lips, a layer of silicone rubber adhesive between said lips and adjacent panel and extending continuously about and being substantially coextensive with said lips, and means on said spacer frame for mounting said window unit on an oven door, said window unit being free of metal members extending from the outer surface of one of said panels to the outer surface of the other.

References Cited UNITED STATES PATENTS 2,377,684 6/1945 Firner 126-200 X 2,612,154 9/1952 Mills 126-200 2,710,994 6/1955 Mills 126-200 X 2,909,814 10/1959 Schwartz 126-200 X 3,168,089 2/1965 Larkin 126-200 X 3,170,456 2/1965 Moss et al 126-200 X 3,250,268 5/1966 More et al. 126-200 KENNETH W. SPRAGUE, Primary Examiner, 

1. A WINDOW UNIT FOR AN OVEN DOOR COMPRISING A PAIR OF SPACED TRANSPARENT PANELS, A SPACER FRAME BETWEEN SAID PANELS, SAID SPACER FRAM EXTENDING CONTINUOUSLY ABOUT AN AIR SPACE BETWEEN SAID PANELS AND WITH SAID PANELS SUBSTANTIALLY SEALING SAID AIR SPACE, SAID SPACER FRAME HAVING A PAIR OF PERIPHERAL LIPS EXTENDING CONTINUOUSLY ABOUT SAID SPACER FRAME, ONE ADJACENT EACH OF SAID PANELS, AND ADHESIVE LAYER BETWEEN EACH OF SAID LIPS AND THE ADJACENT PANEL SECURING AND SEALING SAIS PANEL TO SAID SPACER FRAME, AND MOUNTING MEANS ON SAID SPACER FRAME FOR MOUNTING SAID WINDOW UNIT ON AN OVEN DOOR, SAID ADHESIVE LAYERS AND SAID MOUNTING MEANS CONSTITUTING THE SOLE MEANS SUPPORTING SAID PANELS ON SAID OVEN DOOR. 